In the two decades since the development of audio compact discs, the progression of standards for physically mastering data on optical discs has been matched by a corresponding evolution in the logical approaches to encoding the data. Thus, the progression from single data layer discs with pits mastered along a continuous spiral to multiple data layer discs with zoned wobbled grooves has been matched by a corresponding evolution from the eight-to-fourteen modulation of CIRC-encoded digitized audio data to the sophisticated data encoding strategies established for DVD video and DVD-RAM.
Yet the disparate approaches to the logical encoding of data over the past two decades of optical disc evolution all share one fundamental characteristic: in each case, the data-encoding scheme is known at the time decoding must be effected; without such a predetermined encoding scheme, the decoding chipset could not thereafter accurately recreate the stored information. For readers or reader/writers that maintain backwards-compatibility with earlier standards, the chipset accommodates each (or at least a subset) of the earlier, prior-established, determinate encoding schemes.
Copending and commonly owned U.S. patent application Ser. Nos. 09/183,842 filed Oct. 30, 1998, 09/311,329 filed May 14, 1999, and 60/134,368 filed May 14, 1999, incorporated herein by reference in their entireties, describe optical discs that possess concurrently readable nonoperational structures. During trackable reading of these novel discs, the nonoperational structures produce signals that are discriminably embedded within the normal operational electrical responses. These signals report physical properties of the nonoperational structures. As might be expected, however, the signals from the nonoperational structures so inspected match no pre-established encoding standard. There thus exists a need in the art for analytical methods, software, and devices that permit the signals produced by such nonoperational structures to be identified, analyzed, and thereby decoded. More generally, there exists a need in the art for analytical methods, software, and devices that permit the post-acquisition decoding of signals acquired from optical media lacking a predetermined encoding scheme.